Hard disc drive (HDD) systems typically include a stack of data storage disks with concentric tracks containing information and rotated by a spindle motor. Transducing heads or read/write heads carried by a slider are used to read from and write to a data track on the disks, with each disk surface being accessible by a dedicated read/write head. The disks in the stack are in a fixed position relative to one another and are not movable axially, i.e., in a direction parallel to the axis of rotation of the spindle motor. Each read/write head is formed on an air-bearing slider attached to one end of a suspension, and each suspension is attached at its other end to a rigid arm of the actuator.
In order to access information quickly (e.g., for reading and writing data to a disk), a typical HDD will have a read/write head positioned adjacent to each disk surface that is available to read or write data. In such a configuration, the cost of having a read/write head for each disk surface is a relatively large portion of the cost of the HDD, especially in HDDs having large numbers of disks. In particular, each of the multiple read/write heads requires its own physical supporting structures, cabling connections to the HDD electronics, and the like.
FIG. 1 illustrates an exemplary configuration of a conventional hard disk drive (HDD) system 20. The HDD system generally includes a stack including several magnetic storage disks 22 configured to rotate about an axis 24, an actuation motor 26 (e.g., a voice coil motor), multiple actuator arms 28 and corresponding suspension assemblies 30, each of which includes a load beam and a slider 32 carrying a transducing or read/write head (not visible). Each slider 32 is supported by suspension assembly 30, which in turn is supported by an actuator arm 28. Together, each actuator arm 28, suspension assembly 30 and slider 32 form a head stack assembly (HSA).
Actuation motor 26 is configured to pivot actuator arm 28 about an axis 34 in order to sweep suspension 30 and slider 32 in an arc across a surface of rotating disk 22 with slider 32 “sliding” or “flying” across disk 22 on a cushion of air, often referred to as an air bearing. The read/write head carried by slider 32 can be positioned relative to selected concentric data tracks 36 of disk 22 by a microactuator, not seen in FIG. 1. A stack of co-rotating disks 22 are generally provided with pairs of similar or identical actuator arms 28, suspension assemblies 30, and sliders 32 that carry read/write heads for reading and writing the top and bottom surfaces of each disk 22 in the stack. Thus, an exemplary HDD having a 4-disk stack with eight accessible surfaces will include actuator arms, suspension assemblies, and sliders to support eight read/write heads.
Because there is pressure in the industry to lower the cost per unit of data for individual HDD systems, there is an increasing desire to eliminate components and/or provide less expensive components for drives, while maintaining quality and accuracy.